1. Field of the Invention
The present invention relates broadly to cooking devices and apparatuses, particularly magnetic induction ranges. More particularly, the present invention relates to a magnetic induction range providing multiple cooking modes and an ability to automatically heat cooking vessels and other objects using RFID technology and temperature sensing, and an ability to read and write recipe or heating instructions using the RFID technology and to interactively assist in their execution.
2. Description of the Prior Art
It is often desirable to automatically monitor and control the temperature of food in a cooking or heating vessel using non-contact temperature-sensing means. Early attempts to do so include, for example, U.S. Pat. No. 5,951,900 to Smrke, U.S. Pat. No. 4,587,406 to Andre, and U.S. Pat. No. 3,742,178 to Harnden, Jr. These patents disclose non-contact temperature regulation devices and methods employing magnetic induction heating, including using radio frequency transmissions to communicate temperature information between the object to be heated and the induction heating appliance, in an attempt to control the induction heating process. More specifically, in Smrke, Andre, and Harnden a temperature sensor is attached to the object to be heated to provide feedback information which is transmitted in a non-contact manner to the induction appliance. In each case, aside from manual inputs by a user, changes to the induction appliance's power output are automatic and based solely upon information gathered and transmitted by the temperature sensor.
No known employment of the aforementioned prior art technology has resulted. However, other attempts to monitor and control the temperature of a vessel during cooking or holding using non-contact methods employing magnetic induction heaters and other electric hobs have been employed in the marketplace. Bosch, a major appliance manufacturer, has, for example, recently introduced ranges and cooking vessels that, together, provide a system using temperature feedback, based on temperature information gathered from the external surface of the vessel, to allow for automatically varying power output to the vessel and thereby control its temperature. As described in a paper titled “Infrared Sensor to Control Temperature of Pots on Consumer Hobs”, authored by Uwe Has of Bosch-Siemens Hausgerate GmbH, Bosch's system employs an infrared sensor that is an integral part of the cooking hob. The infrared sensor is mounted on a cylindrical casing that is designed to direct the infrared sensing beam onto a specific portion of the cooking vessel at a height of approximately thirty millimeters above the bottom of the vessel. The temperature information gathered from the infrared sensor beam is used to alter the power output of the hob. Unfortunately, Bosch's infrared system suffers from a number of limitations, including, for example, an undesirably extreme sensitivity to changes in the emissivity of the region of the vessel on which the infrared sensor beam is directed. If the vessel's surface becomes soiled or coated with oil or grease, the emissivity changes and, as a result, the perceived or sensed temperature is not the actual temperature.
A cooking system comprising an induction range, marketed by Scholtes, and an accompanying infrared/radio frequency sensing device called the “Cookeye”, marketed by Tefal, moves beyond the functionality of the Bosch range system. The Cookeye sensing unit rests upon the handle of the cooking vessel and directs an infrared sensor beam downward onto the food within the vessel to sense the temperature of the food. The Cookeye unit converts the temperature information into a radio frequency signal that is transmitted to a radio frequency receiving unit within the induction range. This radio frequency temperature information is used to alter the power output of the hob to control the temperature of the vessel. Furthermore, the system provides six preprogrammed temperatures, with each temperature corresponding to a class of foods, that the user can select by pressing a corresponding button on a control panel. Once one of the preprogrammed temperatures has been selected, the hob heats the vessel to that temperature and maintains the vessel at that temperature indefinitely. Unfortunately, the Scholtes/Tefal system also suffers from a number of limitations, including, for example, an excessive sensitivity to the emissivity of the food surfaces within the pan. Furthermore, though the six preprogrammed temperatures are an improvement over the Bosch product, they are still too limiting. Many more selectable temperatures are needed to most effectively or desirably cook or hold different types food.
It is also often desirable that a cooking apparatus provide features that allow for or facilitate substantially automatic preparation of culinary dishes. Attempts to design such a cooking apparatus include, for example, U.S. Pat. No. 4,649,810 to Wong. Wong discloses the broad concept of a microcomputer-controlled, integrated cooking apparatus for automatically preparing culinary dishes. In use, the constituent ingredients of a particular dish are first loaded into a compartmentalized carousel which is mounted on the cooking apparatus. The apparatus includes a memory for storing one or more recipe programs, each of which may specify a schedule for dispensing the ingredients from the carousel to a cooking vessel, for heating the vessel (either covered or uncovered), and for stirring the contents of the vessel. These operations are performed substantially automatically under the control of the microcomputer. Unfortunately, Wong suffers from a number of limitations, including, for example an undesirable reliance on a contact temperature sensor that is maintained in contact with the bottom of the cooking vessel by a thermal contact spring. Those with ordinary skill in the art will appreciate that such temperature measurements are notoriously unreliable because the contact is often not perfect when the vessel is placed upon the probe.
U.S. Pat. Nos. 6,232,585 and 6,320,169 to Clothier describe an RFID-equipped induction system that integrates an RFID reader/writer into the control system of the induction cooktop so as to utilize stored process information in an RFID tag attached to a vessel to be heated and to periodically exchange feedback information between the RFID tag and the RFID reader/writer. This system allows many different objects to be uniquely and automatically heated to a pre-selected regulation temperature because the required data is stored on the RFID tag. Unfortunately, Clothier suffers from a number off limitations, including, for example, that it does not employ real-time temperature information from a sensor attached to the vessel. Furthermore, the system does not allow the user to manually select a desired regulation temperature via a control knob on the range's control panel and have the hob substantially automatically achieve that desired temperature and maintain it indefinitely regardless of temperature changes in the food load. Thus, with Clothier, the user could not, for example, fry frozen food in a fry pan without continually having to manually adjust the power output of the hob during the cooking process.
Due to the above-identified and other problems and limitations in the prior art, an improved mechanism is needed for cooking and heating.